<dependency>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-test</artifactId>
    <scope>test</scope>
</dependency>

<dependency>
    <groupId>junit</groupId>
    <artifactId>junit</artifactId>
    <version>4.12</version>
    <scope>test</scope>
</dependency>

package com.sdt;

import com.sdt.mapper.UserCertMapper;
import org.springframework.beans.factory.annotation.Autowired;
import lombok.extern.slf4j.Slf4j;
import org.junit.Test;
import org.junit.runner.RunWith;
import org.springframework.boot.test.context.SpringBootTest;
import org.springframework.test.context.junit4.SpringRunner;

@Slf4j
@RunWith(SpringRunner.class)
@SpringBootTest
public class SignAndVerifyManagerApplicationTests {

    @Autowired
    private UserCertMapper userCertMapper;

    @Test
    public void contextLoads() {
        int keyId = userCertMapper.selectKeyId("sfdjfdjfsdjfsdfjdkfjsdjffk231231231231231213123123123fdsfsfdsfsdf2");
        log.info("keyId=={}", keyId);
    }

}

springboot单元测试相关依赖